Integrated Touch and Force Sensor Shielding
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Solution Overview
Problem
Combining touch and force sensors with a display in electronic devices often results in electrical noise that impairs the performance of both the touch sensor and the display, due to the integration of user input with the display screen.
Innovation Solution
Integrating a touch sensor and a force sensor into the display stack with a shared drive source, where the force sensor acts as an electrical shield for the touch sensor, reducing electrical noise and isolating it from other device components, allowing both sensors to operate over overlapping time periods without significant cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch sensor and force sensor are integrated with display screen, then user input functionality is combined with display, but electrical noise impairs performance of touch sensor and display
Solution Approach 1:
The sensor system is segmented into distinct functional layers: touch-sensor electrodes for touch detection, force-sensor drive electrode, and force-sensor sense electrode for force detection. This segmentation allows each component to perform its specific function while reducing electrical interference between them, resolving the contradiction between integrated functionality and performance reliability.
Solution Approach 2:
The force-sensor drive electrode serves as an intermediary electrical shield positioned between the touch-sensor electrodes and other device components. This intermediary layer reduces electrical noise and interference reaching the touch sensor, thereby maintaining sensor performance reliability while preserving the integrated display functionality.
2Device complexity
If touch sensor and force sensor share common drive source, then device complexity is reduced, but electrical interference between sensors may increase
Solution Approach 1:
The force-sensor drive electrode acts as an intermediary shield that reduces electrical interference between the shared drive source and the touch-sensor electrodes. This allows the system to benefit from the simplified common drive source configuration while mitigating the potential electrical interference through the shielding effect of the intermediary force-sensor drive electrode.
Solution Approach 2:
The force-sensor drive electrode provides localized electrical shielding specifically in the region between the touch sensor and other device components. This local quality enhancement针对性地 addresses electrical interference issues without requiring complete separation of the sensor systems, maintaining the benefits of the shared drive source.
3Object-affected harmful factors
If force-sensor drive electrode is positioned below touch-sensor electrodes, then shielding effect is achieved, but manufacturing layers increase
Solution Approach 1:
The force-sensor drive electrode serves multiple functions: it acts as a drive electrode for force sensing and simultaneously functions as an electrical shield for the touch sensor. This multi-functionality reduces the need for additional dedicated shielding layers, simplifying the manufacturing process while achieving effective electrical noise reduction.
Solution Approach 2:
The shielding function is merged with the force-sensor drive electrode rather than being a separate component. By combining the shielding function with an existing functional element, the patent avoids increasing the number of manufacturing layers while still achieving effective electrical noise shielding for the touch sensor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the performance of both touch and force sensors by reducing electrical interference, enhancing the reliability of user input and display operations, particularly in in-cell sensing configurations where electrodes are shared.
Implementation Method 1
a portion of the force sensor may function as an electrical shield for the touch sensor, which may reduce electrical noise and may help isolate the touch sensor from other aspects of the device
Implementation Method 2
The first array of electrodes may be configured to sense a touch on the cover using a capacitive sensing scheme
Implementation Method 3
The force-sensor drive and sense electrode may be configured to sense a force on the cover
Data Source
AI summary
Systems and method of performing touch and force sensing in an electronic device. The device includes a cover and an array of touch-sensor electrodes disposed below the cover. The first array of electrodes may be configured to sense a touch on the cover using a capacitive sensing scheme. The device also includes a force-sensor drive electrode disposed below the first array of electrodes and a force-sensor sense electrode disposed below the force-sensor drive electrode. The force-sensor drive and sense electrode may be configured to sense a force on the cover. The device also includes a shared drive circuit having an output that is operatively coupled to the array of touch-sensor electrodes and the force-sensor drive electrode.